"Maybe they're not even Russians, but Ukrainians, Tatars, Jews, just with Russian citizenship. Even that needs to be checked.

"Maybe they have dual citizenship. Or maybe a green card. Maybe it was the Americans who paid them for this work. How do you know? I don't know."

'Classic anti-Semitic stereotypes'

Mr Putin has been criticised by some groups, including the Anti-Defamation League (ADL).

"President Putin bizarrely has resorted to the blame game by pointing the finger at Jews and other minorities in his country," ADL chief executive Jonathan Greenblatt said in a statement.

Image copyrightReutersImage caption
Ms Kelly interviewed the Russian president at the Kremlin in Moscow

"It is deeply disturbing to see the Russian president giving new life to classic anti-Semitic stereotypes that have plagued his country for hundreds of years, with a comment that sounds as if it was ripped from the pages of the Protocols of the Elders of Zion."